Objective: To explore the molecular mechanism for a case with para-Bombay phenotype caused by α-1,2-fucosyltransferase (FUT1) gene mutations.
Methods: Blood phenotype of the propositus was determined by standard serological testing. Polymerase chain reaction-sequence specific primer (PCR-SSP) and direct sequencing of PCR product were used to analyze its ABO genotype. The PCR product of FUT1 gene was sequenced and analyzed.
Results: The phenotype of the propositus was initially detected as para-Bombay A type. Direct sequencing of ABO gene showed that the genotype of the proband was A101/O01 (261G/del), which was consistent with the result of PCR-SSP. Two homo-mutations, 35C>T and 658C>T, were detected in the FUT1 gene by sequencing, and the genotype was determined as h(35T+658T)/h(35T+658T).
Conclusion: h(35T+658T)/h(35T+658T) is responsible for the para-Bombay phenotype of the propositus. The genotype is rare even in para-Bombay populations.